Protons, neutrons, and electrons in atoms | Atomic structure | High school chemistry | Khan Academy

Introduction

This tutorial provides a clear overview of the atomic structure, focusing on the three main subatomic particles: protons, neutrons, and electrons. Understanding these particles is crucial for high school chemistry and lays the foundation for more advanced studies in chemistry and related fields.

Step 1: Understand the Basic Structure of Atoms

• Atoms are the fundamental building blocks of matter.
• They consist of three main subatomic particles:
  • Protons: Positively charged particles found in the nucleus.
  • Neutrons: Neutral particles (no charge) also located in the nucleus.
  • Electrons: Negatively charged particles that orbit around the nucleus.

Practical Advice:

• Visualize the atom as a mini solar system, where the nucleus (containing protons and neutrons) is the sun, and electrons are the planets orbiting around it.

Step 2: Learn About Protons

• Protons have a mass of approximately 1 atomic mass unit (u).
• The number of protons in an atom determines the element and its atomic number.

Practical Advice:

• Familiarize yourself with the periodic table, as the atomic number (number of protons) defines each element. For example, hydrogen has 1 proton, while carbon has 6.

Step 3: Understand Neutrons

• Neutrons are similar in mass to protons, also about 1 u.
• They do not affect the charge of the atom but contribute to its mass.

Practical Advice:

• The number of neutrons can vary among atoms of the same element, leading to different isotopes. For example, carbon-12 has 6 neutrons, while carbon-14 has 8.

Step 4: Explore Electrons

• Electrons have a much smaller mass, about 0.0005 u.
• They carry a negative charge and are arranged in energy levels or shells around the nucleus.

Practical Advice:

• Remember that the arrangement of electrons determines the chemical properties of an element. The first shell can hold up to 2 electrons, while subsequent shells can hold more (8, 18, etc.).

Step 5: Relate the Particles to Atomic Behavior

• The balance of protons and electrons determines the overall charge of an atom.
  • If an atom has more electrons than protons, it becomes negatively charged (anion).
  • If it has more protons than electrons, it becomes positively charged (cation).

Practical Advice:

• Practice drawing atoms, showing the correct number of protons, neutrons, and electrons for various elements. This will help reinforce your understanding.

Conclusion

Understanding protons, neutrons, and electrons is essential for grasping atomic structure and the behavior of elements in chemistry. Start by familiarizing yourself with the periodic table and the role of each subatomic particle. As you advance, explore how these particles interact in chemical reactions and compounds, setting a strong foundation for your chemistry studies.